Evolving Epidemiology of Hepatitis C Virus in the United States

The impact of hepatitis C virus (HCV) infection on health and medical care in the United States is a major problem for infectious disease physicians. Although the incidence of HCV infection has declined markedly in the past 2 decades, chronic infection in 3 million or more residents now accounts for more disease and death in the United States than does human immunodeficiency virus (HIV)/AIDS. Current trends in the epidemiol-ogy of HCV infection include an apparent increase in young, often suburban heroin injection drug users who initiate use with oral prescription opioid drugs; infections in nonhospital healthcare (clinic) settings; and sexual transmission among HIV-infected persons. Infectious disease physicians will increasingly have the responsibility of diagnosing and treating HCV patients. An understanding of how these patients were infected is important for determining whom to screen and treat. The first descriptions of the epidemiology of hepatitis C virus (HCV) infection date well before both the actual identification of the virus in 1989 [1] and the US Food and Drug Administration’s approval of tests to detect antibody to hepatitis C virus in 1992. “Non-A, non-B hepatitis ” was identified as a cause of chronic liver disease among transfusion recipients in studies during the 1970s in the United States [2] and abroad [3]. Since then, hepatitis C in this country has gone from an unknown and untreatable infection, mainly identified when transmitted through receipt of blood or hemodia-lysis, to an identifiable and curable—but underappre-ciated—infection today. In this article, we review trends in incidence, prevalence, mortality, and mode of trans-mission of HCV infection in the United States